689664 has 40 divisors (see below), whose sum is σ = 1841400. Its totient is φ = 229376.

The previous prime is 689641. The next prime is 689693. The reversal of 689664 is 466986.

It is a nialpdrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1312 + ... + 1760.

It is an arithmetic number, because the mean of its divisors is an integer number (46035).

2⁶⁸⁹⁶⁶⁴ is an apocalyptic number.

689664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 689664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (920700).

689664 is an abundant number, since it is smaller than the sum of its proper divisors (1151736).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

689664 is an equidigital number, since it uses as much as digits as its factorization.

689664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 470 (or 454 counting only the distinct ones).

The product of its digits is 62208, while the sum is 39.

The square root of 689664 is about 830.4601134311. The cubic root of 689664 is about 88.3512135001.

The spelling of 689664 in words is "six hundred eighty-nine thousand, six hundred sixty-four".